The present invention relates to a blank gumming method for cigarette packing machines.
More specifically, the present invention relates to a blank gumming method for cigarette packing machines wherein each blank is mated with a respective group of cigarettes, and is folded about the group to form a container, the blank presenting a central portion defining the front wall, the rear wall and two first end walls of the container, and two lateral portions on either side of the central portion and defining, by at least partial superimposition, two second end walls of the container.
Here and hereinafter, the term "cigarette packing machine" is intended to mean both a packing machine in the real sense of the word, i.e. a machine for receiving loose cigarettes and conditioning them into containers consisting of packets formed from respective flat blanks of cardboard or similar, and an overwrapping machine, i.e. a cartoning or boxing machine for receiving the cigarettes already conditioned inside packets or cartons, and for further conditioning them into containers formed from respective flat blanks of cardboard or similar.
For the sake of simplicity, the following description refers, purely by way of example, to actual cigarette packing machines.
GB A-2091162 and EP A-601411 relate to the formation of so-called rigid, hinged-lid packets from a blank made of cardboard or similar, and which, when withdrawn from a feedbox, is placed, still flat, onto a conveyor, and is fed to a spray gumming station where all the portions of the blank to be connected stably to other parts of it and to the group of cigarettes to be conditioned are gummed simultaneously.
The above method presents several drawbacks. In particular, since the blank is folded as it travels through a succession of folding stations distributed along a relatively long folding path, all the in-process packets located along the folding path and downstream from the gumming station must be rejected in the event of stoppage of the packing machine.